I guessed what the issue was (well not re them not working properly but that they looked terrible and did not talk to the screen etc) within your first line where the dealer would retrofit the sensors.
How did the sale go, did you give them a spec, agree a price and then they say we can get you this car quicker we just need to retrofit the front sensors, if they did then you may have an argument.
If however you enquired about available cars saw/heard of the one with no sensors and asked them to fit front sensors and did not specify they were oe spec then you may be on a sticky wicket.
I personally would have double checked and had it specifically noted on the contract that all parts were Volvo original equipment as the car with the front sensors will probably have a different front bumper with the holes already in it so the sensors sit flush to the bumpers rather than on the top of the bumper.
I guess you realise the ones they have fitted are a £50 universal system they fit to to the used shopping trollies where people have to choose from limited stock as clearly can not choose the factory option as a factory built car.
Good luck with this but Volvo may not do much and say this is nothing to do with them as it is nothing really to do with the car they built but simply an issue between you and the dealer re how they delivered it to you